醇盐水解—水热法制备纳米ATO超细粉体及其导电性能研究

实验以SnCl4.5H2O作为锡的阳离子源,以SbCl3或SbCl5为锑的阳离子源,以醇盐水解—水热法制得了纳米级的高导电性能的ATO超细粉体。采用热重—差示扫描量热(TG-DSC)、X射线衍射(XRD)、电阻率测定等测试方法系统研究了锑掺杂量、反应pH值、热处理等对ATO粉体粒径和导电性能的影响。实验结果表明:本实验制得的ATO超细粉体样品粒径在10 nm左右,并且超细粉体的分散性能良好,导电性优于国内同类产品。     

纳米锑掺杂氧化锡的研究进展

介绍了纳米锑掺杂二氧化锡(ATO)材料独特的光电机理;系统综述了目前国内外纳米ATO粉体的主要制备方法,包括各制备方法的工艺路线与特点;并对纳米ATO在显示涂层材料、导电抗静电涂料、透明隔热涂料等领域中的应用进行了概括.最后,结合纳米ATO的光电特性,针对纳米ATO材料的制备与应用研究面临的问题提出几点建议.     

热处理对掺锑二氧化锡纳米棒结构和导电性能的影响

以SnCl4·5H2O和SbCl3为原料,采用化学共沉淀法制得纳米级掺锑二氧化锡(ATO)的前驱物,在一定条件下热处理,成功制备了直径为10～30nm,长为50～500nm的金红石结构的ATO纳米棒.运用热重分析(TGA)、X射线衍射(XRD)、透射电镜(TEM)及比表面仪(BET法)对纳米棒进行了表征,初步探讨了其形成机理,较系统地研究了热处理温度及热处理时间对粉体形貌结构和导电性能的影响规律.     

工艺参数对ATO复合涂料抗静电性能的影响

研究了主要工艺参数对ATO抗静电涂料导电性能的影响,用渗滤模型分析了导电填料含量对涂层导电性能的影响;填料表面处理实验表明,偶联剂能提高ATO的最大填充量。另外,讨论了基体树脂种类、固化工艺对涂层导电性能的影响,并确定了优化的工艺参数。     

ATO包覆纳米ZnO粉体的制备及表征

采用液相沉积法对纳米氧化锌进行表面包覆ATO改性,用自制粉体电阻测定仅对掺杂粉体导电性能进行测定,利用Zate电位测定仪考察包覆前后纳米ZnO在水体系中的分散稳定性,采用SEM、TEM对导电粉体进行分析.讨论了不同ATD掺杂量和煅烧温度对包覆粉体体积电阻率的影响.结果表明,ATO在氧化锌表面形成均匀的包覆层,最佳掺杂量30%左右,最佳煅烧温度约520℃,有效改变了氧化锌的等电点,提高了纳米氧化锌在水中的分散稳定性.     

超细导电粉末改性聚氨酯弹性体及其性能表征

将偶联剂处理过的ATO超细导电粉末(SnO2 Sb2O3)添加到聚氨酯(PU)基体中,经过超声混匀和高速搅拌,制备了抗静电性能良好的PU弹性体。探讨了影响ATO分散性及PU抗静电性能的主要因素,并研究了ATO对PU弹性体的力学性能与热性能的影响。实验结果表明:ATO经硅烷偶联剂处理后,在超声波分散和高速搅拌的条件下不易团聚,能在PU中较均匀地分散;PU添加导电粉末ATO后具有较好的抗静电性,拉伸强度、断裂伸长率和热稳定性均有所提高。     

锑掺杂二氧化锡(ATO)导电粉体的研究进展

介绍了锑掺杂二氧化锡(ATO)的特点、导电机理、制备方法研究现状及目前存在的问题.ATO具有良好的导电性、浅色透明性、稳定性、粒子纳米化及多功能性,指出氧空位和Sb5+在SnO2禁带形成施主能级并向导带提供n型载流子是ATO导电的两种主要机理,主要介绍了液相法中常用制备超细ATO粉体的方法:沉淀法、溶胶一凝胶法和醇盐水解法,最后指出了制备超细ATO粉体存在的问题及解决方法.     

PMMA/ATO纳米复合材料的结构与导电性能

采用溶液共混的方式制备了聚甲基丙烯酸甲酯/纳米掺锑二氧化锡(PMMA/ATO)复合材料,分析了复合材料的微观相态结构及导电性能,并对复合材料的物理机械性能及热性能进行了研究.结果表明:经过钛酸酯偶联剂处理的纳米ATO在PMMA基体中分散良好,在含量较低的情况下即可获导电性能良好的复合材料;当纳米ATO的质量分数为5%时,复合材料具有良好的物理机械性能;纳米ATO在PMMA基体中起到了交联点的作用,使其玻璃化转变温度随着ATO的增加而升高,从而改善了PMMA的耐热性能.     

尿素水解法制备(1-x)SnO2·xSb2O3导电颜料的研究

以尿素为沉淀剂,利用均匀沉淀法制备(1-x)SnO2*xSb2O3导电颜料(以下简称ATO);探讨了导电机理,对不同制备方法进行了对比;研究了主要工艺参数及煅烧温度对颜料导电性能影响.     

制备工艺对ATO纳米棒形貌结构的影响

以SnCl4·5H2O和SbCl3为原料,采用化学共沉淀法成功制备了高含量棒状纳米级掺锑二氧化锡(ATO)导电粉体,研究了掺锑量、热处理温度及热处理时间对纳米棒形貌结构的影响。初步探讨了ATO纳米棒的形成机理,并用热重分析(TG)、透射电镜(TEM)、X-射线衍射(XRD)、比表面法(BET)对棒结构进行了表征。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.